Beneficial insects join fight against costly aphids

Published 9:45 am, Monday, September 7, 2015

Image 1of/1

Caption

Close

Image 1 of 1

Blayne Reed

Blayne Reed

Beneficial insects join fight against costly aphids

1 / 1

Back to Gallery

As the current growing season begins to wind down, area producers are finding a welcome ally bringing large numbers of reinforcements to this year’s battle against the sugarcane aphid and other costly crop pests.

Blayne Reed, in his weekly Plains Pest Management newsletter, reports that in recent days predator insects have been rallying, particularly in sorghum fields that have been hard hit by the quickly spreading aphids.

The integrated pest management AgriLife Extension specialist for Hale, Swisher and Floyd counties, Reed reports that some of the earliest planted corn fields have been harvested, with the rest are generally awaiting dry down.

The bulk of the area’s mid-maturity corn is in late dough to dent stage and progressing well, Reed says, while late-planted fields are in blister to early dough stage, and at peak water use. A few select fields of late-planted corn are showing limited increases in disease pressure. “Drier conditions and few heavy morning dews, despite moving into September, are likely to thank for the problem omission so far,” he says.

The majority of Reed’s program sorghum fields are in a milky dough stage to coloring dough, although crop maturity ranges from whorl stage all the way to harvest. “It is clear that all area fields have been hit by the sugarcane aphid to some extent,” Reed reports.

After examining various sorghum fields after being treated to control damaging levels of sugarcane aphids, Reed and fellow Extension entomologists notes that fields that experienced superior control generally do not show the need to follow-up chemical applications.

Secondly, “the predator population (is) the highest I have seen in my career (and) continues to grow,” Reed remarks.

The entomologists, according to Reed, suspect that in sorghum fields that received “really good control from our treatments, whether it be first or second, predators have finally reached a high enough level to have a major impact.” In those fields, Reed says, predators seem to be able to clean up remaining populations of sugarcane aphids. However, in fields that show marginal control from initial pesticide applications, the same level of predators are having difficulty controlling larger numbers of sugarcane aphids.

“There is a chance, now that the predators appear to be at a high enough level to be of major assistance behind a good treatment,” Reed observes, “that one good hit on these SCA could carry us to black-line stage. It also underscores the need to make each SCA treatment count by utilizing proven rates, plenty of water and silicone-based surfactants.”

While the sugarcane aphid continues to draw the majority of attention, Reed warns that spidermites have been a serious problem this season in many corn fields. “In our program, we have treated 90 percent of our mid-maturity state corn this season, but did not add any new fields to the total this week.” Predators, environmental conditions and good control contributed to reduction in spidermite numbers, he says. Producers still need to remain vigilant in late-planted and slower maturing fields, he adds.

While spidermites have been detected in sorghum, Reed says it’s apparent that spidermites and sugarcane aphids do not coexist well in the same leaf location.

Concerning cotton, Reed found no open bolls in his program fields as of the end of the week, but expects to spot some soon. He does not expect any major pest issues this week, based on last week’s observations. “Our predator populations are very good to excellent in most fields,” he noted.